The Automated Assessment of Constructed Response project (AACR) uses clustering and data modeling techniques to aid in the evaluation of student written responses. Text analysis is accomplished using IBM SPSS Modeler, which is capable of identifying important concepts in student text responses. These responses are then placed into categories and can then be used as variables in cluster analysis to identify students with similar responses to a question prompt. We used AACR to help us investigate students’ ideas about chemistry topics such as intermolecular forces and acids and bases as part of a larger study on how students develop the ability to determine chemical and physical properties from a molecular structure. Preliminary findings will be presented regarding the use of both automated analysis and human coding to explore students’ ideas about intermolecular forces and acid-base chemistry.